The main driver behind study participation by patients in Brazil, one of the fast-growing BRIC (Brazil, Russia, India and China) economies and a key destination for global outsourcing of clinical development, is altruism not personal health or financial gain, a new meta-analysis has found.

The insight belies the impression that limited access to medicines or general poverty is the principal motivator for patient recruitment in developing compared with developed markets for clinical trials. 

In fact, monetary reimbursement was the least of four leading factors that influenced trial participation in Brazil, discovered the researchers from that country’s Pontificia Universidade Católica do Paraná, Duke University in the US and Singapore, and Kalpavriksha Healthcare and Research Healthcare and Research in India.

On the other hand, Brazilian patients were also found more willing than their counterparts in another BRIC country, India, to take part in clinical trials – something the researchers suggested could be at least partly down to Brazil’s generous publicly funded healthcare system relative to India. 

While 48% of the Indian patients studied reported personal health benefits as the major factor influencing willingness to participate (WTP) in clinical trials, in Brazil the corresponding figure was only 29%, the researchers noted.

The study published in the open-access journal PLoS One was a systematic review and meta-analysis of WTP among patients in Brazil. A system dynamics model was then used to compare the results with those of a similar study by the same research group of WTP among patients in India.

Once relevance and inclusion/exclusion criteria had been applied, the Brazilian review boiled down to five clinical trials in total. From these, the researchers gauged WTP in terms of four factors favouring participation in clinical trials and the same number of factors acting as a barrier to participation.

The factors weighing in favour of participation, together with the corresponding percentages of patients who cited them, were as follows:

Altruism (55%). This included both the possibility of benefiting others and the opportunity to help scientific progress.

Personal health benefits (30%). Some patients were interested in the possibility of consultations with specialists, a more in-depth consultation with the same doctor or even the chance to consult at all, as there was no health service in that particular city. Others were influenced by the opportunity to find out more about their disease or to gain free benefits such as HIV tests, snacks or bus tickets.

Convenience (11%). Not having to wait a long time for a consultation as well as access to medicines and tests at no cost were the reasons cited here.

Monetary reimbursement (6%). This was one of the least cited factors, even in a study that involved only patients on low incomes.

The factors that served as a barrier to participation in clinical trials in Brazil were:

Fear of adverse events (12%). Three of the five studies included in the analysis were HIV vaccine trials. Concerns about side-effects related both to the vaccine itself and to fear that it could infect patients with HIV.

Mistrust (6%). Some patients said they felt insecure about the trial and needed more information before deciding whether to participate. Other reasons cited included the fear of being used as guinea-pigs or that a vaccine would fail, as well as distrust of government, drug companies, research scientists or the United States.

Lack of knowledge (4%). In the study concerned, this factor stemmed from not having enough information about the vaccine used.


Inconvenience (2%). This included reasons such as the clinic being too far from home and the need to have injections.

Based on the results of the meta-analysis, the best way of motivating Brazilian patients to participate in clinical trials is “by making them understand the altruistic side of the trial rather than trying to give monetary incentives”, the authors commented. “Another essential point is to explain to the patients about possible side-effects.”